In the filtering art, particularly where high temperature viscous material is being filtered, it has been customary to design a particular housing and filter element for each filter application. Typically, the filter elements have been relatively large in size to provide the desired filter area and flow rates needed. Such custom designs necessitate the user maintaining a large inventory of special parts. Typically, these filter elements are constructed of material which may be cleaned so that the filter element may be repeatedly used. Where a custon filter element of large size is used, such cleaning often requires the construction of special cleaning equipment. In addition, where a large single filter element is utilized, any damage to the filter media requires a replacement of the entire filter element at a large cost to the user. Obviously, the provision of special filter elements and cleaning equipment to fit special applications results in higher costs than would be encountered where a large number of standard type filter elements could be used for various applications.
In some large commercial operations, where fluids such as plastics are being filtered, it is extremely important that a filter element is removable rapidly from the flow of fluid being filtered to a cleaning station to preclude the fluid being filtered from solidifying and rendering the filter elements unusable for future applications. Thus, the filter elements must be easily removed and replaced within the housing.
The prior art patents known to applicants which relate to this area are U.S. Pat. Nos. 2,921,686; 2,946,446; 1,919,570; 2,572,971; 3,092,577; 3,268,442; 3,118,837; 2,859,876; 3,833,121; 3,028,627; 3,353,211; 3,488,806; 2,661,497; 2,763,308; 2,786,504; 3,007,199; 3,112,525; 3,145,746; 3,033,256; 3,059,276; 3,193,877; 3,243,849; 3,455,357; 3,480,706; 3,50l,806; 3,503,096.